<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="lib/vue.js"></script>
</head>
<body>
    <div id="root"></div>
</body>
<script>
    const data = {
        a:1,
        b:2
    }
    const vm = new Vue({
        el:"#root",
        data,
        created(){

            setTimeout(()=>{
                console.log(vm===this,this.a,this.b);
            });

        },
        methods:{
            run(){
                this.a = 100;
                // console.log(this===vm,this.a,this.b);
            }
        }
    })
    vm.run();
    console.log(data.a,vm.$data.a);
    // console.log(vm.$data === data);// true
</script>
</html>